The effects of serotonin, dopamine, octopamine and tyramine on behavior of workers of the ant Formica polyctena during dyadic aggression tests.

We investigated the effect of injections of four biogenic amines (serotonin, dopamine, octopamine and tyramine) on behavior patterns displayed by workers of the red wood ant Formica polyctena during dyadic confrontations with four types of opponents: a nestmate, an alien conspecific, an allospecific ant (Formica fusca), and a potential prey, a nymph of the house cricket (Acheta domesticus). Significant effects of biogenic amine administration were observed almost exclusively in the case of confrontations with allospecific opponents. Serotonin treatment exerted stimulatory effects on behavior patterns involving physical aggression (biting accompanied by gaster flexing, dragging and formic acid spraying), but these effects were relatively weak and/or documented by indirect evidence.

Brain GABA and glutamate levels in workers of two ant species (Hymenoptera: Formicidae): interspecific differences and effects of queen presence/absence.

Presence of amino acid neurotransmitters gamma-aminobutyric acid (GABA) and glutamate (Glu) in ant brains was reported in very few studies. To learn more about factors influencing GABA and Glu levels in ant brains, we applied high-performance liquid chromatography to measure levels of these compounds in single brains of workers of 2 ant species, Myrmica ruginodis (subfamily Myrmicinae) and Formica polyctena (subfamily Formicinae) taken from queenright/queenless colony fragments and tested in dyadic aggression tests consisting of an encounter with a nestmate, an alien conspecific or a small cricket. Brain glutamate levels were higher than those of GABA in both tested species.

Pharmacological characteristics of zolpidem-induced catalepsy in the rat.

Zolpidem is a non-benzodiazepine hypnotic drug acting preferentially at α1-containing GABAA receptors expressed in various parts of the brain, including the basal ganglia. The aim of the present study was to provide preliminary characteristics of zolpidem-induced catalepsy in Wistar rats. Zolpidem (2.

Neonatal serotonin (5-HT) depletion does not affect spatial learning and memory in rats.

Background: Extensive previous research has suggested a role for serotonin (5-HT) in learning and memory processes, both in healthy individuals and pathological disorders including depression, autism and schizophrenia, most of which have a developmental onset. Since 5-HT dysfunction in brain development may be involved in disease etiology, the present investigation assessed the effects of neonatal 5-HT depletion on spatial learning and memory in the Morris water maze (MWM).

Methods: Three days old Sprague-Dawley rats were pretreated with desipramine (20 mg/kg) followed by an intraventricular injection of the selective 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT, 70 μg).

Neonatal serotonin (5-HT) depletion does not disrupt prepulse inhibition of the startle response in rats.

The neurodevelopmental hypothesis of many brain disorders is based on the notion that environmental factors have significant effects on brain maturation. Because serotonin (5-HT) dysfunction in development may be involved in disease etiology, the present investigation assessed the effects of neonatal 5-HT depletion on prepulse inhibition of the startle response (PPI) in rats. Three-day-old Sprague-Dawley rats were pretreated with desipramine (20 mg/kg), followed by an intraventricular injection of the selective 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT, 70 μg dissolved in 2 μl of 0.

Cocaine self-administration in Warsaw alcohol high-preferring (WHP) and Warsaw alcohol low-preferring (WLP) rats.

Individuals prone to drug self-administration may be vulnerable not only to a single drug reinforcer but to a variety of drug reinforcers. It has been shown that two thirds of alcoholics regularly use drugs other than ethanol (alcohol). Up to 30% of alcohol-dependent patients report concurrent misuse of cocaine.

The influence of neonatal serotonin depletion on emotional and exploratory behaviours in rats.

Recent studies have shown that neurodevelopmental disturbances in the structure and function of the brain are significant factors in the onset of psychiatric disorders. Such deficits may also affect neurotransmission. Among the different neurotransmitter systems, serotonin (5-HT) plays an important role in the organisation and maturation of brain structures during development.

Diverse behavioral, monoaminergic and Fos protein responses to opioids in Warsaw high-alcohol preferring and Warsaw low-alcohol preferring rats.

Predisposition to addictions is presumably related to a dysfunction of the brain reward system, which can be 'compensated' by the intake of different psychoactive drugs. Hence, animals showing propensity for developing dependence to a specific drug class may also be useful for modeling other addictions. We compared the effects of repeated (14 daily doses) morphine (10 mg/kg) or methadone (2 mg/kg) treatment followed by a 2-week withdrawal and a morphine challenge (5 mg/kg) on locomotor activity, brain Fos expression and selected brain regional levels of dopamine, serotonin and their metabolites in the 38th generations of selectively bred Warsaw low-alcohol-preferring (WLP) and Warsaw high-alcohol-preferring (WHP) rat lines.

Stress-opioid interactions: a comparison of morphine and methadone.

The utility of methadone and morphine for analgesia and of methadone for substitution therapy for heroin addiction is a consequence of these drugs acting as opioid receptor agonists.We compared the cataleptogenic and antinociceptive effects of single subcutaneous doses of methadone hydrochloride (1-4 mg/kg) and morphine sulfate (2.5-10 mg/kg) using catalepsy and hot-plate tests, and examined the effects of the highest doses of the drugs on Fos protein expression in selected brain regions in male Sprague-Dawley rats.

Post-session injections of a protein synthesis inhibitor, cycloheximide do not alter saccharin self-administration.

A large body of evidence indicates that reactivation of aversive memories leads to protein synthesis-dependent memory reconsolidation which can be disrupted by cycloheximide (CHX) and other protein synthesis inhibitors. The aim of the present study was to investigate whether CHX would alter maintenance of well-trained instrumental responding for 0.1% saccharin.

Effects of cycloheximide on extinction in an appetitively motivated operant conditioning task depend on re-exposure duration.

Little is known about the role of new protein synthesis in extinction of operant responding for natural and chemical reinforcers. In the present study, the authors investigated whether the effects of a protein synthesis inhibitor, cycloheximide (CHX) on extinction of operant responding for sweet reward depended on the duration of re-exposure sessions. In addition, the authors investigated whether the effects of CHX on extinction could generalize to relapse of saccharin seeking induced by discrete cues.

The effect of cannabinoid CB(1) receptor antagonist rimonabant (SR-141716) on ethanol drinking in high-preferring rats.

The present study investigated the effect of the cannabinoid CB(1) receptor antagonist, rimonabant (SR-141716) on ethanol intake in selectively bred alcohol-preferring Warsaw High-Preferring rats. Ethanol (10% vol/vol) and food were available in daily 4-h limited access period while water was available ad libitum. The administration (i.

Warsaw high-preferring (WHP) and Warsaw low-preferring (WLP) lines of rats selectively bred for high and low voluntary ethanol intake: preliminary phenotypic characterization.

The Warsaw High Preferring (WHP) and Warsaw Low Preferring (WLP) lines were bred from Wistar foundation stock to obtain lines of rats that differ in their preference for ethanol solutions. The WHP line has met several major criteria for an animal model of alcoholism. The WHP rats voluntarily drink excessive amounts of ethanol while the WLP rats consume negligible amounts of ethanol.

Alcohol relapse induced by discrete cues activates components of AP-1 transcription factor and ERK pathway in the rat basolateral and central amygdala.

Alcohol-related cues may induce relapse to heavy alcohol drinking and promote molecular adaptations in discrete brain regions. An exact nature of these molecular alterations is still unknown. In the present study, rats trained to self-administer ethanol were tested for cue-induced reinstatement of ethanol seeking after 30 days of abstinence.

Active versus passive cocaine administration: differences in the neuroadaptive changes in the brain dopaminergic system.

There is considerable evidence that chronic exposure to cocaine is associated with low striatal dopamine D2 receptor availability. In the present study we wished to determine whether neuroadaptive changes in densities of D2 receptors were due to direct pharmacological actions of cocaine or they reflected motivational states that were present when cocaine injection depended on active drug-seeking behavior and whether these changes were related to the actual expression of D2 mRNA. To achieve this goal we utilized a "yoked" procedure in which rats were tested simultaneously in groups of three, with only one rat actively self-administering cocaine while the other two received yoked injections of either cocaine or saline.

Ethanol blocks nicotine-induced seizures in mice: comparison with midazolam and baclofen.

Low doses of ethanol may antagonize the pharmacological effects of nicotine. Recently, it has been shown that the effects of ethanol on nicotine discrimination are not correlated with blood ethanol levels. The aim of the present study was to evaluate whether ethanol (0.

History of cocaine self-administration alters morphine reinforcement in the rat.

It has been shown repeatedly that cocaine pre-exposure may sensitise neurochemical and behavioural responses to opioid drugs. The aim of the present study was to investigate effects of a prior history of cocaine self-administration on morphine reinforcement in the rat. Male Sprague-Dawley rats were allowed to acquire intravenous cocaine self-administration (0.

Operant self-administration of ethanol in Warsaw high-preferring (WHP) and Warsaw low-preferring (WLP) lines of rats.

The results of the present experiment demonstrate that ethanol-preferring line of rats (WHP), and ethanol-nonpreferring line of rats (WLP) are able to acquire and maintain lever pressing reinforced by EtOH (oral operant EtOH self-administration) under FR-1 and FR-2 schedule of reinforcement. On the other hand, WHP rats but not WLP rats, displayed the high ability to acquire and maintain robust lever pressing for EtOH under FR-3 procedure. These data suggest that EtOH possesses stronger reinforcing properties in WHP rats.

Cycloheximide impairs acquisition but not extinction of cocaine self-administration.

The aim of the present study was to assess the role of de novo protein synthesis in the acquisition and extinction of cocaine self-administration. In a first experiment, rats were trained to respond for intravenous cocaine infusions (0.3 mg/kg) and a protein synthesis inhibitor, cycloheximide (CHX; 3 mg/kg, s.

Effects of ethanol on nicotine-induced conditioned place preference in C57BL/6J mice.

It has been shown that small doses of ethanol ( View Article and Find Full Text PDF

Nicotine-induced conditioned taste aversion in the rat: effects of ethanol.

It has been shown that small doses of ethanol antagonise the discriminative stimulus properties of nicotine in the rat. The aim of the present study was to evaluate whether ethanol could antagonise the aversive stimulus effects of nicotine. Wistar rats were trained to associate nicotine injections with a novel tasting fluid (0.

Contingency does not contribute to the effects of cocaine self-administration on prodynorphin and proenkephalin gene expression in the rat forebrain.

Neuroadaptations in the brain opioid systems produced by chronic exposure to drugs of abuse may contribute to the drug dependence and addiction. Although regulation of the gene expression of the opioid propeptides proenkephalin (PENK) and prodynorphin (PDYN) by psychostimulants has previously been described, little attention has been paid to dissociating effects of pharmacological actions of the drugs from those produced by motivational processes driving active drug intake in self-administration paradigms. In the present study, effects of response-dependent (contingent) and response-independent (noncontingent) cocaine administration on the PENK and PDYN gene expression in the rat forebrain have been directly compared using the "yoked" self-administration procedure.

Effects of 5,7-dihydroxytryptamine lesion of the dorsal raphe nucleus on ethanol discrimination in the rat.

It has been shown that ethanol produces a complex interoceptive cue in rodents with distinct GABAergic, glutamatergic, and serotonergic (5-hydroxytryptamine, 5-HT) components. The present study aimed to examine the contribution of the 5-HT system originating in the dorsal raphe nucleus (DRN) to the discriminative stimulus effects of ethanol in male Wistar rats. Therefore, selective lesions of 5-HT neurons in the DRN were induced by microinfusions of 5,7-dihydroxytryptamine.

Self-reported effects of methadone on cigarette smoking in methadone-maintained subjects.

Subjects maintained on methadone evidence a high level of interest in quitting cigarette smoking. Readiness to quit may result, at least partially, from direct pharmacological interactions between methadone and brain nicotinic acetylcholine receptors. The aim of the present study was to assess: (1) self-reported changes in smoking habits after admission to a methadone maintenance treatment (MMT) program; (2) acute effects of methadone administration on smoking behavior in MMT patients.

Extended blockade of the discriminative stimulus effects of nicotine with low doses of ethanol.

The aim of the present study was to further evaluate effects of ethanol on nicotine discrimination and to correlate these effects with blood ethanol levels. Rats were trained to discriminate 0.3 mg/kg nicotine from its vehicle in the standard two-lever operant procedure.